Structure for anatomical suppport with frame and convex cushioned plate for back, headrest and seat, for seating in general, especially seats in motor vehicles, with manual and motor-driven adaption of cushioned plate covexity and position

ABSTRACT

Structure for anatomical support for the back, headrest and seat components of chairs in general and especially seats in motor vehicles comprising a frame, a convex cushioned plate fitted with sliding means in relation to the frame and pull-push cables, the first end of which is fixed to one or other end of the cushioned plate, freely sliding inside a sheath whose first end is fixed, on the frame, to one or other of the ends of the cushioned plate, while the second end of said push-pull cable and of said sheath is fixed to control devices for adjusting the position of the cushioned plate if the first end of the sheath is fixed to the frame, or for adjusting convexity of the cushioned plate if the first end of the sheath is fixed to said plate.

The invention concerns cushioned plates shaped for the back, headrestand seat for seating in general, especially in motor vehicles.

Wide use is made of cushioning inside seat backs, especially in thebacks of car seats, where its position can be varied longitudinally, ascan also convexity of the support, to suit the user's preference.

The devices required to provide these variations are generally complexand costly, and somewhat awkward to manage by the user.

The above invention enables the position of the cushioned plate, and itsconvexity, in the seat back as well as in the headrest and on the seat,to be varied with the greatest ease by means of simple electricalcontrols, as will now be explained.

Subject of the invention is a structure for anatomical support in theback, headrest and seat components of seating in general especially inmotor vehicles.

The structure comprises a convex cushioned plate fitted with means forsliding it in relation to the frame, and push-pull cables the first endof which is fixed to one or other end of the cushioned plate, freelysliding in a sheath the first end of which is fixed to the frame or toone or other end of the cushioned plate.

The second end of said push-pull cable and of said sheath is fixed tooperating devices mounted on the fixed structures of said components ofthe seat.

By moving the push-pull cable in both directions, said devices adjustthe position of the cushioned plate if the first end of the sheath isfixed to the frame, or convexity of said cushioned plate if the firstend of the sheath is fixed to said plate.

The two ends of the sheath are respectively fixed to the cushionedplate, to the frame and to the control devices by an anchoring meanscomprising a tubular body with partially elastic ends which permitforced insertion of the end of the sheath, and a safety ring movablefrom an idle position to the area of the tubular body in which the endof the sheath has been pressed to stabilize it.

Movement in both directions of the push-pull cable inside the sheath isobtained by a cylindrical slider, having two diametral arms at its topand, at its base, a means for holding the end of the push-pull cable,freely sliding within a tubular body that presents two longitudinalslits in which said diametral arms freely move.

Said tubular body fits inside a sleeve in whose inner wall are helicalgrooves the dimensions of which permit a freely sliding movement of theends of said diametral arms, projecting through the slits.

In the bottom of said grooved sleeve is a device for holding the sheath.The end of the push-pull cable emerging from said sheath is fixed to theslider.

It follows that, by using the control devices to make said tubular bodyrotate, the slider with its arms is forced, by the simultaneous effectof the longitudinal slits in the tubular body and by the helical groovesin the sleeve, to translate in relation to the sheath, in one directionor in the other according to the direction of rotation impressed upon itby the tubular body, thus adjusting the position of the cushioned plate,or its convexity, in relation to the frame.

When the tubular body has terminated rotation in one direction or theother, the ends of the slider's arms enter in one or other of the pairsof transversal grooves at the two ends of the longitudinal slits, sostabilizing the adjusted position or convexity of the cushioned platedetermined by said rotation of the tubular body.

In the control devices, rotation of the tubular body in either directionis done either manually by means of a knob, or by an electrically drivenratiomotor connected to a switch respectively at the sides of the seatback, of the headrest and of the actual seat itself.

Placed at the sides of the seating components, namely of the back,headrest and seat, are two control devices for respectively adjustingthe position or convexity of the cushioned plate, one device for eachcomponent.

In one type of execution the first end of the sheath is fixed to one endof the frame and a first end of the push-pull cable to one end of thecushioned plate so that, having determined translation, by means of thecontrol devices to which the second ends of the push-pull cable and ofthe sheath are fixed, and of said cable in relation to the sheath, thecushioned plate can be adjusted in relation to the frame.

In one execution the frame and cushioned plate are made in a singlepiece.

The two components are associated by a hinge of the same material butthinner, allowing the cushioned plate to be bent over onto the frame.

At the end of the frame opposite to the hinge, rods, present at the freeend of said cushioned plate, can be inserted and slide freely in twolateral slots.

A first end of the sheath is fixed to the frame while the first end ofthe push-pull cable is fixed to the free end of the cushioned plate.

In this way, having determined, by means of the control devices to whichthe second ends of the push-pull cable and sheath are fixed, translationof said cable in relation to the sheath, it becomes possible to adjustconvexity of the cushioned cable.

A manual multiple control device comprises insertion, around the groovedsleeve that carries the knob, of a rotating sleeve to which is fixed atriangular lever, having an end sufficiently projecting in relation tothe knob, and comprising a rotatable finger knob.

A device for anchoring a sheath is attached to a longitudinal tab fixedto said grooved sleeve.

On said rotating sleeve is another longitudinal tab fixed to which isthe head of one end of the push-pull cable, sliding inside said sheath.

By rotating the knob it is therefore possible to move the push-pullcable in both directions inside a sheath inserted in the anchoringdevice at the base of the grooved sleeve and, using the knob forshifting the triangular lever, move the push-pull cable sliding inside asheath inserted in the anchoring device fixed to the tab attached to thegrooved sleeve.

From the foregoing it is clear that, using the control knob, convexityof the cushioned plate can be adjusted in relation to the frame, whilethe same may be done to its position using the knurled finger knob.

In one type of execution the frames are joined to the fixed structure ofthe seat by helical springs.

In one type of execution the fixed structure is created, both in theback and seat components, by a transversal metal band shaped to extendsubstantially all round the perimeter of these components.

In one type of execution the ratiomotor for the electric motor isepicycloidal.

The invention offers evident advantages.

Simple and convenient means are employed to adjust the cushioned platein the back, headrest and seat, of chairs in general but especially inthe seats of motor vehicles.

The position of controls at the sides for adjusting lengthwise positionof the cushioned plate and convexity in the back, headrest and seatfacilitates such adjustments especially when the vehicle is moving.

In the execution with an electric motor, the user simply uses theswitches placed in convenient positions respectively for the back, theheadrest and the seat.

The execution presenting the multiple knob and lever controlrespectively for adjusting the position and convexity of a cushionedplate, is both inexpensive and convenient to operate.

The execution in which the frame and the cushioned plate come in asingle piece is less costly both as regards components and assembly. Tosum up these advantages, the various executions described enable theuser to achieve a high degree of comfort by application of cushionedplates, both in ordinary seating as well as that in a motor vehicle,ensuring a restful position, especially during a long journey and evenin stressful traffic conditions.

The simplicity, economy and comfort provided for users can make possiblea universal application of an invention so especially suited to motorvehicles.

Characteristics and purposes of the disclosure will be made stillclearer by the following examples of its execution illustrated bydiagrammatically drawn figures.

Plate 1/11, FIG. 1 The back of a car seat with built-in headrest,illustrating the cushioned plate operated, using a push-pull cablesliding in a sheath and transmission, by a control device with knob andassembly, shown at minimum level and at minimum convexity, perspectivewith graphic break and detail of the transmission.

Plate 2/11, FIG. 2 Means of control with knob, assembly comprising aslider with arms and a grooved sleeve and with the ends of the push-pullcable and sheath, at the first terminal position of the slider,perspective with graphic break.

Plate 2/11, FIG. 3 The control device in FIG. 2, exploded view.

Plate 3/11, FIG. 4 As in FIG. 3 with the push-pull cable fixed in theslider with arms fitted into the assembly and with the sheath insertedin the base of the grooved sleeve.

Plate 3/11, FIG. 5 The control device at the second terminal position ofthe slider, perspective.

Plate 4/11, FIG. 6 Seat back with cushioned plate set higher up,perpsective view, cut away.

Plate 5/11, FIG. 7 Back with cushioned plate given greater convexity,perspective view, cut away.

Plate 6/11, FIG. 8 Seat in a motor vehicle with headrest built into theback, and separate view of the seat, perspective view cut away.

Plate 7/11, FIG. 9 Seat as above with motor driven control devices,perspective view, cut away.

FIG. 10 Motor driven control device, perspective.

FIG. 11 Electrical connections for motor driven device.

Plate 8/11, FIG. 12 Execution of frame in a single piece with cushionedplate lying flat, view from the front.

FIG. 13 Execution in FIG. 12 with cushioned plate on the frame, frontview.

Plate 9/11 FIG. 14 As in FIG. 13, back view.

FIG. 15 As in FIG. 14, lateral section drawn at axis AA.

FIG. 16 As in FIG. 14, partial lateral section at axis BB.

FIG. 17 As in FIG. 15, greater convexity of cushioned plate

Plate 10/11 FIG. 18 Multiple manual device with second control in thefirst position, perspective.

FIG. 19 As above with second control in second position, perspective.

Plate 11/11 FIG. 20 Seat back served by multiple control, perspective,cut away.

FIG. 1 shows a seat 5 in a motor vehicle comprising the seat component6, the back 7 and built-in headrest 8.

In the back 7, the metal reinforcement 10 supports the frame 15, withuprights 18 and cross pieces 19,21, by means of a set of helicaltraction springs 25 fixed at their two ends respectively in the holes 13in the reinforcement 10 and in the holes 22 in the frame 15.

The elastic rectangular cushioned plate 40, slightly convex lengthwise,is placed between the uprights of the frame 15, said plate beingadjustable in position and convexity as required by the seated person.The upper and lower ends of the cushioned plate 40 are kept rigidrespectively by bars 42, 43 and by rods 45 at the ends, that freelypenetrate in the slots 30, 31 on the inner sides of the frame 15.

The control device 90, with knob 92, is placed at on side of the back 7.By means of the pull-push cable 80 freely sliding in the sheath 70, andthrough the transmission device 50 (FIG. 1) fixed to the upper crosspiece 19 of the frame 15, said knob 92 is used to adjust the position ofthe cushioned plate.

The control device 90 (FIGS. 2-5) comprises the assembly 91 and controlknob 92 with collar 93 and longitudinal diametral ribs 94.

Said collar 93 on the knob penetrates inside the tubular cylindricalbody 97 guided by ribs 94 that enter the longitudinal diametral cavities98 said collar 96 and are stabilized by means not shown for simplicity.The tubular body 97 presents two longitudinal slits 100 and 101 at theends of which are branches of equal width with cavities 102 and 103facing opposite ways.

Inserted into said tubular body 97, with a suitable amount of play, isthe cylindrical slider 110 at one end of which are the two diametralarms 116 and 117 whose diameter corresponds, with a suitable amount ofplay, to the width of the longitudinal slits 100, 101 in said tubularbody 97.

At the other end of said slider 110 is a chamber 111 with window 112 atthe bottom of which is the slit 113 with bevelled corners 115 and cavity114 bounded by the opposing projections 118.

Inside this cavity the push-pull cable 80 will be inserted by pressure.Close to its base the sleeve 120 presents anchoring tabs 122 and, on itsinternal walls, a pair of helical grooves 123 and 124, open at the rimof said sleeve 120, of a constant width corresponding to the diameter ofthe arms 116, 117 of the slider 110.

The internal diameter of said sleeve 120 corresponds, with a suitableamount of play, to the external diameter of the tubular body 97 and, onits internal wall close to the lower end 125, presents a circumferentialgroove 126 the dimensions of which correspond to those of the projectingrim 106 with a sloping inward-facing wall at the end of said tubularbody 97.

Said lower end 125 of the sleeve 120 extends to the cylindricalextension 130 of an internal diameter slightly greater than that of theslider 110, followed by the moderately elastic tubular anchorage 131 forthe sheath that presents diametral pairs of internal and external heads,respectively 132 and 133.

The internal diameter of said anchorage 131 corresponds to the externaldiameter of a sheath 70 at the second end of which are recesses 76.

The safety ring 135, with internal recesses 136, can be placed roundsaid, anchorage 131 for the sheath.

During assembly, the push-pull cable 80 in the sleeve 120 is pressedinside the slit 113 in the base of the slider 110 where pressure,exerted by the sides of the slit and by the head 82 (FIG. 4), holds itin position.

Sheath 70 enclosing said push-pull cable 80 is inserted inside anchoringmeans 131 and stabilized there by the heads 132 (FIG. 4) that penetrateinside the recesses 76 in said sheath, and by pressure from the safetyring 135 with its internal recesses 136, which ring moves from the idleposition 135′ to position 135 shown in FIG. 5. Slider 110 is theninserted in the tubular body 97 causing the arms 116, 117 to penetrateinside slits 100 and 101 respectively (FIG. 4). Said tubular body 97 isthen inserted into the sleeve 120 so that the ends of arms 116 penetrateinto the helical grooves 123 and 124 respectively, as far as insertionof the projecting rim 106 on the tubular body 97 in the circumferentialgroove 126 (FIG. 5) at the lower end of the sleeve 120 creating thepositions as illustrated in FIG. 2.

In FIG. 2 the arms 116, 117 of the slider 110 are inside the cavities102 at the end, here called the bottom, of the slits 100 and 101 andtherefore the pull-push cable 80 assumes the position shown at point Ain FIG. 2 corresponding to the lower level of the cushioned plate 40 asshown in FIG. 1.

In FIG. 5 rotation of the knob 92 has caused the arms 116, 117 of theslider 110 to emerge from the cavities 102 and, guided by the helicalgrooves 123 and 124, these have moved to the starting point, here calledthe top, of the slits 100 and 101 after which translation of thepush-pull, cable 80 to the position 80′ at point B (FIG. 5) haspositioned the cushioned plate 40 as shown in FIG. 6, namely at a shortdistance from the cross piece 19 (FIG. 6).

Extension 11 of the reinforcement 10 and extension 16 of the frame 15are shown.

The cushioned plate 170, smaller but substantially the same as thecushioned plate 40 for the back, is guided by pairs of slits 34 and 35and by short rods 175 at the ends of the bars 171 and 172 which, at thetop and bottom respectively, strengthen said cushioned plate 170. Fixedon the upper cross piece 28 of extension 16 of the frame 15 is thetransmission device 185 connected to the control device 190, with knob192, by the push-pull cable 180 with its sheath 182

Said push-pull cable 180 is fixed by the block 187 to the upper bar 171of the cushioned plate 170.

Also fixed by a block 207 to said bar 171 is the cable push-pull 200with sheath 202 connected by the transmission device 205 to the means ofcontrol 210 with knob 212.

The seat 6 presents the frame 225 supported by reinforcement 221 bymeans of springs 230 hooked to the holes 227 of the frame and 222 of thereinforcement respectively.

The cushioned plate 230, substantially the same as the cushioned plate40 for the back but slightly larger, is placed between the uprights ofthe frame.

The rear and front ends of said cushioned plate 240, are made rigid bythe bars 242 and 243 with short rods 245 at their ends, said rods freelypenetrating inside the pairs 235, 236 of slits made in the inner sidesof the frame 225.

On the side 220 of the seat 6, the control device 260 with knob 262 maybe seen applied to the reinforcement 221, for adjusting the position ofsaid cushioned plate 240.

Knob 262 controls the position of the cushioned plate 240 by means ofthe pull-push cable 250, freely sliding in the sheath 252, and throughthe transmission device 255 fixed to the rear cross piece 233 of theframe 225.

It will be seen in FIG. 8 that rotation of the knob 262 has set theposition of the cushioned plate 240 at a short distance from the rearcross piece 233 of the frame 225.

To adjust convexity of the cushioned plate 240, transmission device 275is fixed to its front bar 243 and is connected by the push-pull cable270 with sheath 272 to a second control device 280 with knob 282 mountedon the side 200 of the seat 6.

The transmission devices 255, 275, control devices 260, 280 aresubstantially identical to the transmission 50 and control devices 90respectively, and therefore need no specific description.

The different numbering serves solely to indicate the changed function.FIG. 9 illustrates the seat 290 in which the control devices, with knobsfor adjusting the position and convexity of the cushioned plates 40,170, 240 respectively of the back 7, headrest 8 and seat 6, are replacedby motor-driven controls.

These devices are obtained by connecting the assembly 91, shown in FIGS.2-5, to an electric ratiomotor instead of to the knob 92.

FIG. 10 illustrates the device 300 for motor-driven control to adjustthe position of the cushioned plate 40 in the back 7.

This device comprises the assembly 91 already described except that itpresents the fixing tabs 102 at the side 122 instead of at the bottom.In the cylindrical seat 96 of the tubular body 97 of said assembly 91,the shaft of the ratiomotor 295 has been coupled, connected to theelectric motor 296 presenting the electrodes 301 and 303.

The control device so obtained is numbered 300.

To adjust convexity, a device 305 is included connected by the firstconductor 306 to the switch 307.

In FIG. 9 the other motor-driven control devices for adjusting positionand convexity of the cushioned plate substantially present the samecharacteristics as those of the device 300 already described.

To adjust its position, the cushioned plate 170 in the headrest 8 isserved by the device 310 connected through the first conductor 311 tothe switch 312 and, for adjusting convexity, by the device 315 connectedthrough the conductor 316 to the switch 317.

To adjust its position, the cushioned plate 240 in the seat 6 is servedby the device 320 connected through the first conductor 321 to theswitch 322 and, for adjusting convexity, by the device 325 connectedthrough the conductor 326 to the switch 327.

The second conductor for the motor-driven devices listed above and thesecond of the related switches, are respectively connected to the twopoles of the battery 330 through conductors 331 and 332; these areexplained by the diagram in FIG. 11 as it is difficult to include themin graphic form in FIG. 9.

FIGS. 12-17 illustrate a slightly convex cushioned plate 350 formed of asingle piece having a frame 351 that can be used, especially for theback of a seat, in motor vehicles.

This product can be pressed in suitable material and thereforeinexpensively, and can obviously be made in different sizes,specifically proportioning the different parts, according to the type ofseat or chair and according to preferences.

In FIG. 12 the frame 351 presents cross bars 352 at the top, 355 at thebottom, 353 and 354 and others in between.

The cushioned plate 350, with its holes 357, is mounted onto the bottomcross bar 355 by means of the hinge formed of a thin strip 360, shown indetail in the enlarged view, FIG. 13, said strip being thinner than theframe 351.

After pressing, it is therefore a simple matter to bend back saidcushioned plate onto the frame as seen in FIG. 13.

This position is rendered stable by the pair of rods 365 formed at theends of the reinforcing bar 364 at the top of the cushioned plate 350(FIG. 14).

Pairs 370 of these rods 365 are fitted into seats close to the cross bar353 of the frame 351.

In these seats the bars can freely move for their full lengths.

In a tongue-shaped part 375 at the upper end of the cushioned plate is ahole 376 reached through the cut 377 with bevelled ends 378, as seen inthe enlargement.

Fitted to the rear of cross bar 354 is a transmission device 380substantially similar to the transmission device 50 already shown in thedetail of FIG. 1 of this description.

By means of this device the head 391 holds the cable 390 and the sheath392 then made stable by the safety ring.

By connecting the cable-sheath unit to a knob controlled device, such as90, 190, 260 for manual operation, or to devices 300, 310, 320, alreadydescribed, for motor-driven control, it is clear that convexity of thecushioned plate 350 can be adjusted as desired, as may be seen in FIG.17.

FIGS. 18 and 19 illustrate a multiple device 400 for double control. Inthe first case control is exerted by knob 162 which, by means of thegrooved sleeve 120 and sheath holder 131, enables the push-pull cable150 to be moved freely in both directions inside the sheath 152. In thesecond case control is exerted by a rotating sleeve 401 that freelysurrounds the grooved sleeve 120 and extends for a short distance beyondthe anchoring tabs 122.

At the top, matching with the knob 162, said sleeve 401 presents acontrol lever 402 with a triangular end whose vertex carries anorthogonal pin 405 round which the cylindrical vertically knurled fingerknob 406 freely rotates.

Close to the end of the sleeve 401, on the longitudinal lateral edge ofa longitudinal rectangular window 410, said sleeve presents alongitudinal tab 415 to support the push-pull cable 80 with head 81.

In said tab is a hole 416 for the push-pull cable 80 at the bottom of aslit 417 in which said cable can be pressed down, entry beingfacilitated by the bevelled opening 418.

Once so inserted, the head 81 of the push-pull cable 80 is held in thecasing 420 with upper hole 421, at the back of the tab 415.

Said window 410 admits the bracket 430 longitudinally fixed to the endof the grooved sleeve 120 to which bracket is fixed the sheath holder431 with safety ring 432.

The foregoing explains how said multiple control device 400 makespossible double control as a substitute, shown by the example in FIG.20, for the two controls 90 and 160 illustrated in FIG. 6.

The sheath 152 remains held in place by the sheath holder 131 forguiding the push-pull cable 150, while the sheath 70 is inserted in thesheath holder 431 fixed to the bracket 430 at the end of the groovedsleeve 120 (FIG. 19).

It follows that, turning the knob 162 adjusts convexity of cushionedplate 40 in the back 7, and using the finger knob 406, the lever 402 canbe rotated to adjust the position of said cushioned plate 40.

1. Structure for anatomical support in the back, headrest and seatcomponents of seating in general, especially in motor vehicles,characterized in that the structure comprises a frame, a convexcushioned plate fitted with means that slide in relation to the frame,and with push-pull cables, the first end of which is fixed to one orother end of the cushioned plate, freely sliding inside a sheath whosefirst end is fixed to the frame or to one or other of the ends of thecushioned plate, while the second end of said push-pull cable and ofsaid sheath is fixed to control devices mounted on the fixed structuresof said components of the seating, which devices determine, by movingthe push-pull cable in one direction or the other, adjustment of theposition of the cushioned plate if the first end of the sheath is fixedto the frame, or adjustment of convexity of the cushioned plate if thefirst end of the sheath is fixed to said plate.
 2. Structure as in claim1, characterized in that the two ends of the sheath are respectivelyfixed to the cushioned plate, to the frame and to the control devices bymeans of an anchoring device comprising a tubular body with a partiallyelastic end into which the end of the sheath can be pressed, and asafety ring transferable from an idle position to the area of thetubular body into which the end of the sheath has been pressed to holdit stable.
 3. Structure as in claims 1 and 2, characterized in thatmovement of the push-pull cable in both directions inside the sheath isobtained by a cylindrical slider at the top of which are two diametralarms and at whose base is a means for anchoring the end of the push-pullcable freely sliding within a tubular body in which are twolongitudiinal slits in which said diametral arms can freely slide, saidtubular body being fitted inside a sleeve with internal helical grooves,of a size sufficient to allow the ends of said diametral arms emergingfrom the slits to slide freely, there being in the bottom of saidgrooved sleeve a device for anchoring the sheath, the end of thepush-pull cable emerging from said sheath being fixed to said slider sothat, on causing said tubular body to rotate by means of the controldevices, the slider with arms is guided by the longitudinal slits in thetubular body and the helical grooves in the grooved sleeve, and made totranslate in relation to the sheath, in one direction or in the otheraccording to the direction of rotation impressed on the tubular body, soadjusting the position or convexity of the cushioned plate in relationto the frame.
 4. Structure as in claim 3, characterized in that, onconcluding rotation of the tubular body in one direction or in theother, the ends of the slider arms enter one or other of the pairs oftransversal grooves made at the two ends of the longitudinal slits sostabilizing adjustment of the position or convexity of the cushionedplate determined by rotation of the tubular body
 5. Structure as inclaim 3, characterized in that, in the control devices, rotation of thetubular body in both directions, is made manually by a knob. 6.Structure as in claim 3, characterized in that, in the control devices,rotation of the tubular body in both directions is made by an electricratiomotor connected to a switch placed respectively on the side of theback, of the headrest and of the seat.
 7. Structure as in claims 1-6,characterized in that, at the sides of the seating components consistingof the back, headrest and seat, are two control devices for respectivelyadjusting the position or convexity of the cushioned plate in each ofsaid components.
 8. Structure as in claims 1 and 2, characterized inthat the first end of the sheath is fixed to one end of the frame whilea first end of the pull-push cable is fixed to one end of the cushionedplate so that, using the control devices, to which the second ends ofthe push-pull cable and of the sheath are fixed, to make the push-pullcable translate in relation to the sheath, the position of saidcushioned plate can be adjusted in relation to the frame.
 9. Structureas in claim 1, characterized in that the frame and cushioned plate aremade in a single piece by means of a hinge formed of the same materialbut thinner to allow the cushioned plate to be fiolded back on theframe, there being at the end of the frame opposite to the hinge, twolateral slots in which short rods at the free end of said cushionedplate can be inserted and freely slide.
 10. Structure as in claims 1, 2and 6, characterized in that a first end of the sheath is fixed to theframe while the first end of the push-pull cable is fixed to the freeend of said cushioned plate, so that causing, by means of the controldevices to which the second ends of the push-pull cable and of thesheath are fixed, translation of the push-pull cable in relation to thesheath, convexity of said cushioned plate can be adjusted.
 11. Structureas in claims 1-5, characterized in that a device for multiple manualcontrol comprises insertion, round the grooved sleeve that supports theknob, of a rotating sleeve to whiich is fixed a triangular lever thevertex of which projects suitably outward from the knob, on which end isa finger knob, there being fixed to a longitudinal bracket, fixed tosaid grooved sleeve, a device for anchoring a sheath, there being onsaid rotating sleeve a second longitudinal bracket to which is fixed thehead of one end of the push-pull cable sliding inside said sheath,rotation of the knob thus making possible movement in both directions ofthe push-pull cable inside a sheath inserted in the anchoring devicemouinted on the tubular body at the end of the grooved sleeve and, byusing the finger knob to move the triangular lever, determine movementin both directions of the push-pull cable sliding inside the sheathinserted in the anchoring device fixed to the bracket on the groovedsleeve, it thus becoming possible, with said multiple manual control, toadjust the position of the cushioned plate, in relation to the frame, byusing the finger knob, and its convexity by using the knob. 12.Structure as in claim 1, characterized in that the frames are joined tothe fixed structure of the whole seat by helical springs.
 13. Structureas in claim 1, characterized in that, for both the back and the seatcomposing the whole seat, the fixed structure consists of a metal bandplaced crosswise and shaped so as substantially to embrace the entireperimeter of said components.
 14. Structure as in claim 6, characterizedin that the ratiomotor for the electric motor is epicycloidal.